The barn where my Grandfather grew up is still standing in Kansas. I have a watercolor painting of the barn that his BIL painted. I think the info that dakotamaid posted is correct. That is why it is called "exterior" Sounds like a fun project. Because of EB book about Quilts on Barn, there should be info on the internet available. There are even tours!! Good Luck !! Something to look forward to doing in Spring !!